Safety belt reeling device with locking device deactivation in response to coil diameter

ABSTRACT

A self-locking safety belt reeling device for a safety belt system of motor vehicles, comprising a casing and a reeling shaft having at one end an eccentric locking member, is provided. The locking member, depending on a radial deflection resulting from a safety belt-sensitive and vehicle-sensitive locking system, contacts abutments fastened to the casing and locks the reeling shaft. The locking member is coupled with a control disk having first outer toothing and which is lockable by the vehicle-sensitive locking system embodied as a spherical sensor having a sensor lever. The safety belt-sensitive locking system is embodied as a pivotable spring-loaded inertia mass that cooperates with the locking member. The locking member is pivotable into engagement with an inner toothing provided at a bearing cup connected to the casing. The inner toothing is connected to a second outer toothing. The inner toothing and the second outer toothing are mounted on a member which is freely rotatable relative to the bearing cup and which is lockable by an outwardly arranged lever engaging the second outer toothing for rendering the locking systems operational or non-operational. The outwardly arranged lever of the safety belt reeling device has a first arm for engaging the second outer toothing and a second arm for sensing a thickness of the wound safety belt coil. The outwardly arranged lever is pivotably supported at the casing and is forced into engagement with the second outer toothing by a spring.

BACKGROUND OF THE INVENTION

The invention relates to a self-locking safety belt reeling device for asafety belt system in motor vehicles comprising a casing and a safetybelt reeling shaft supported therein with a locking member beingsupported eccentrically at one end of said safety belt reeling shaft,which, depending on a radial deflection controlled by a safety belt-and/or vehicle-sensitive locking system, contacts abutments fastened atsaid casing and locks the safety belt reeling shaft, for which purposethe locking member is coupled to an external toothing of a control discwhich on the one hand is lockable by a vehicle-sensitive system in theform of a spherical sensor and is provided, on the other hand, with thesafety belt sensitive system in the form of a pivotable spring-loadedinertia mass that cooperates with a control lever, whereby the controllever is pivotable into engagement with an inner toothing provided at abearing cup that is fixedly connected to the casing, the inner toothingcorresponding to an outer toothing whereby the inner and outer toothingsare freely rotatable in relation to the bearing cup and are lockable bya lever which is outwardly arranged relative to the inner and outertoothings and serves as a control means for activating and deactivatingthe safety belt-sensitive and the vehicle-sensitive locking system atthe control disc.

A safety belt reeling device of this type is described in DE-OS 34 41532; in the known safety belt reeling device the control means for theactivation or deactivation of the safety belt-sensitive and thevehicle-sensitive locking system is provided in the form of anelectro-magnet which, when excited, brings the lever, cooperating withthe outer toothing that is freely rotatable in the bearing cup which isfixedly connected to the casing, into its engaging position with theouter toothing with the aid of a plunger, whereby the outer toothingbecomes fixed in relation to the bearing cup due to the correspondinginner toothing, so that the inertia control system cooperating with thecontrol disc of the safety belt reeling device is provided with afunctional abutment. If the lever is out of engagement with the outertoothing that is pivotable in the bearing cup, the safety belt-sensitiveas well as the vehicle-sensitive locking systems are both deactivatedbecause in that case no functional abutment exists for the cooperationbetween the control disc and the inertia control system; in thatposition the plunger pushes simultaneously the sensor lever, that isoperating with the outer toothing of the control disc of the sphericalsensor, out of engagement with the control disc.

The known apparatus involves the disadvantage that the control of theactivation and deactivation of the respective locking system via anelectromagnet is expensive, because in addition to the translatorymechanism a special sensor control is required and must be provided for.This also involves weaknesses of the known apparatus, because in theevent of either the magnet or the sensor becoming inoperative or in theevent of faulty signal transmission, the function of the safety beltreeling device in respect of self-locking under operational conditionsof the motor vehicle is no longer ensured if the lever is permanentlyout of engagement with the outer toothing.

A safety belt reeling device has been known from U.S. Pat. No. 3,862,726in which a spring arm of a spring that loads a locking member into alocking position with an outer toothing of a respective safety beltreeling shaft rests at the safety belt coil and senses the thickness ofthe safety belt coil wound onto the safety belt reeling shaft. In orderto avoid the resulting locking of the safety belt reeling shaft by thelocking member when the safety belt is completely removed from thereeling shaft and the spring arm is completely pivoted towards thereeling shaft, additional control devices are required.

It is therefore an object of the invention to improve a safety beltreeling device having the characteristics of the aforementioned type,such that the control of the activation and deactivation of the safetybelt-sensitive and the vehicle-sensitive locking system is simplifiedand the operational reliability of a so designed safety belt reelingdevice is improved.

SUMMARY OF THE INVENTION

The present invention provides that the lever which effects theactivation and deactivation comprises an arm for engaging the outertoothing provided at the bearing cup and a further arm for sensing thesafety belt coil wound onto the safety belt reeling shaft and ispivotally mounted on the safety belt reeling device casing, springbiased towards its engaging position with the outer toothing.

This involves the advantage that any special reception of a controlsignal and its translation is dispensed with. The thickness of thesafety belt coil which is present on the safety belt reeling shaft andis therefore detectable, serves in a simple manner as the controllingfactor for activation and deactivation. More particularly, if the safetybelt has been fully wound onto the safety belt reeling shaft, so thatthe safety belt coil has its maximum thickness, the safety belt isnecessarily in its unfastened condition so that in that case thedeactivation of the safety belt-sensitive and vehicle-sensitive lockingsystem is achieved for the then solely applicable procedure of applyingthe safety belt. For that purpose the corresponding lever for lockingthe outer toothing is advantageously provided with two arms one arm ofwhich adopts the feeler function for sensing the safety belt coil. Achange in thickness of the safety belt coil, due to the presetspringloading of the lever towards its engaging position, leadstherefore automatically to a pivoting of the lever into its engagementposition or its release position, depending on the prevailing thicknessof the safety belt coil.

A further advantage of the invention results from the fact that thesafety belt reeling device may easily be retrofitted with anappropriately designed vehicle-sensitive and safety belt-sensitivelocking system, because it was found that the deactivation of thelocking functions is desirable even in the case of three point safetybelts which are not employed in the context of passive safety beltsystems. Even in the case of conventional three point safety belts, aratchet engagement of the force-absorbing locking elements should beprevented when the safety belt is in the released position in order toavoid jamming of the components of the safety belt reeling device whenthe safety belt is being fastened. Particularly in conjunction with thelevel adjustments of the upper deflection fitting, nowadays gaining inpopularity, such jamming of the safety belt when being fastened can bedisadvantageous, and in the case of an automatic safety belt leveladjustment in conjunction with a seat adjustment mechanism the leveladjustment means may be overloaded and damaged. The aforementionedproblems are advantageously avoidable by the features of the inventionwhich may be provided in a simple manner.

In a preferred embodiment of the invention the reliability of the meansfor activating and deactivating may be increased in that the lever atits end that is opposite the engagement tip and projects beyond itspivoting axis, is provided with a weight which biases the lever towardsits engagement position. Even if the torsion spring, biasing the leverinto its position of engagement, should become inoperative or faulty,the weight will automatically hold the lever in its engaged position sothat in any event the inertia control system finds a functional counterabutment in the outer toothing with the corresponding inner toothing,the outer toothing being held in position by the lever, so that theoverall functional reliability of the safety belt reeling device isensured.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing an embodiment of the invention is illustrated which willbe described in the following. There is shown in:

FIG. 1 a plan view of the so-called system side of a safety belt reelingdevice with the bearing cup partly cut away and the locking systemsbeing deactivated,

FIG. 2 the safety belt reeling device of FIG. 1 with the locking systemsbeing activated,

FIG. 3 a front-sectional view of the safety belt reeling device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In each of the drawings only the means for activating and deactivatingthe safety belt-sensitive and the vehicle-sensitive locking system areillustrated, reference being made to the state of the art according toDE-OS 34 42 532 in respect of further details concerning the function ofthe safety belt reeling device. In principle the drawing is based on aself-locking safety belt reeling device 10 with so-called radial lockingmeans. Although not shown in the drawing, a safety belt reeling shaft ismounted in a U-shaped casing of which only the U-leg 11 that is carryingthe so-called system side of the safety belt reeling device 10 isillustrated. The safety belt reeling shaft penetrates the U-leg 11 witha shaft extension. A safety belt coil 12 is accommodated on the safetybelt reeling shaft and has a thickness which is greatest when the safetybelt is released and which diminishes by unwinding of the safety beltfrom the safety belt reeling shaft during the safety belt applicationprocedure.

A locking member which is radially movable into engagement with atoothing fixed to the casing is eccentrically mounted on the shaftextension. The radial movement between a release and a locking positionis controlled by a control disc 40. The control disc 40 in turn iscontrollable both by the so-called safety belt-sensitive as well as bythe vehicle-sensitive locking system.

The safety belt-sensitive system which is intended to cause locking ofthe safety belt reeling device in the event of sudden pulling-outmovements of the safety belt, is based on the control disc 40 on which aspringloaded inertia mass M is centrally pivotally mounted. A controllever 42 supported on one side of the control disc 40 and adapted to bedeflected outwardly by the inertia mass is provided in the trajectory ofthe possible pivotal movement of the inertia mass.

A bearing cup 13 is mounted in fixed relationship to the casing. Theinner toothing 43 cooperating with the control lever 42 is freelyrotatably mounted on the bearing cup 13 which is supported at the U-leg11. The distance of the inner toothing 43 of the bearing cup 13 to thecontrol lever 42 of the control disc 40 is selected such that thecontrol lever 42 engages the inner toothing 43 of the bearing cup 13,when being deflected due to the movement of the inertia mass M of thecontrol disc 40. The operation of a so designed safety belt-sensitivelocking system is apparent more particularly from the state of the artcited for purposes of type definition.

The vehicle-sensitive system is formed by a spherical sensor 14comprising a sphere 15 accommodated in a cup for translating theacceleration, respectively deceleration movements of the vehicle into amovement of the sensor lever 16 which in turn is adapted for engaging anouter toothing 41 of the control disc 40. Any deflection of the sphere15 from its "normal position" causes the sensor lever 16 to engage thecontrol disc 40 which revolves jointly with the safety belt reelingshaft whereby the control disc 40 is arrested and further rotationalmovement is prevented. The locking member, due to the prescribedfunction thereof, is deflected into the locking position of the safetybelt reeling shaft.

With respect to activation and deactivation of the afore denoted lockingsystems, an outer toothing 17, integrally connected to the innertoothing 43 is provided on the bearing cup 13, the toothings 43, 17being rotatably mounted within the bearing cup 13 on a pinlike extensionof the safety belt reeling shaft.

A two-armed lever 19, one arm 20 of which, with its engaging tip 21,cooperates with the outer toothing 17 that is freely pivotable in thebearing cup 13, and the other arm 22 of which serves as a sensory armfor the safety belt coil 12, is mounted on the U-leg 11 of the casingand is pivotable about a pivoting axis 18. The lever 19 is springloadedtowards its position of engagement (apparent from FIG. 2) by a torsionspring 23 arranged at its pivoting axis 18.

In addition, the lever 19 comprises a projection 24 which in the releaseposition of the lever 19 (apparent from FIG. 1) presses against thesensor lever 16, preventing the latter from swinging out in thedirection of the outer toothing 41 of the control disc 40, even in theevent of movements of the sphere 15 in the cup.

At its rearmost end that is opposite the engaging tip and projectsbeyond the pivoting axis 18, the lever 19 is provided with a weight 25which supports the action of the torsion spring 23 or takes its place inthe event of failure, because due to the predetermined leverage, theengaging tip 21 of the lever 19 is held in engagement with the outertoothing 17 by the weight 25.

As is apparent from FIG. 1, the arm 22 of the lever, in the event of afully wound up safety belt and maximum thickness of the safety belt coil12 in the released position of the safety belt, is pivotedcounter-clockwise against the action of the spring 23, so that in such aposition the engaging tip 21 of the arm 20 of the lever 19 can in noevent engage the outer toothing 17 in the bearing cup 13. The result isthat the outer toothing 17 and thus also the inner toothing 43, coupledtherewith and cooperating with the inertia locking system, is freelyrotatable in the bearing cup 13, so that the control levers have nofunctional counter abutments in the interior of the bearing cup.Accordingly, both the safety belt-sensitive as well as thevehicle-sensitive locking systems are rendered inoperative according tothe position apparent from FIG. 1 when the safety belt coil 12 has itsmaximum thickness.

If, however, the thickness of the safety belt coil is reduced, asillustrated in FIG. 2, due to the fastening process, the unwindingmovement is followed by the sensing arm 22 of the lever 19 in that thearm 19 is pivoted clockwise such that the engaging tip 21 of the lever19 now engages the outer toothing 17, thereby arresting the toothing inthe bearing cup 13 that is fixed to the casing, whereby the function ofthe belt-sensitive locking system of the safety belt reeling device isrendered operational.

The pivotal movement of the lever 19, as it follows the diminishingthickness of the safety belt coil 12, is brought about by the torsionspring 23 which biases the lever 19 into its position of engagementapparent from FIG. 2; even in the event of a malfunction orinoperativeness of this torsion spring, the provision of the weight 25ensures that in any event the operation of the safety belt reelingdevice is ensured, even during failure of the torsion spring.

The features of the subject matter of these documents as disclosed inthe foregoing description, the patent claims, the abstract and thedrawings may be important individually as well as in any combinationwith one another for the realization of the invention in its variousembodiments.

The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

I claim:
 1. A safety belt locking system comprising a casing, a beltreeling shaft supported in the casing for winding and unwinding thesafety belt, a belt-sensitive locking device for the reel to preventunwinding rotation and including a control disc mounted on the shaft,which control disc operates a locking element mounted on the shaft, apivotable spring-loaded inertia mass mounted on the control disc formoving the locking element to engage with inner toothing mounted on thecasing to prevent unwinding rotation of the reel above a predeterminedbelt unwinding speed; a vehicle-sensitive locking device for the reel toprevent unwinding rotation and including an inertia mass sensor mountedon the casing, and a sensor lever movable by the inertia mass sensor toengage toothing formed on the outside of the control disc to actuate thelocking element to prevent reel unwinding rotation in an emergencysituation of the vehicle; means to render the belt-sensitive and vehiclesensitive locking devices operable and inoperable comprising a bearingcup fixedly mounted to the casing, the inner toothing formed on a memberrotatably mounted on the bearing cup, said member also having outertoothing formed thereon, a further lever mounted on the casing forpivoting movement to an engagement position, a spring for biassing thefurther lever to said position, said further lever including a first armmovable to engage the toothing on the member to prevent rotationthereof, a second arm mounted on the further lever for sensing thediameter of the belt on the reel, and a projection on the further leverfor engaging the sensor lever to prevent movement thereof, wherein whenthe belt is wound to said predetermined diameter the first arm of thefurther lever is moved to a position out of engagement with the outertoothing of the member and the projection engages the sensor lever tokeep the sensor lever out of engagement with the outer toothing of thecontrol disc to render the vehicle-sensitive and belt-sensitive lockingsystems inoperable, and when the belt is unwound beyond saidpredetermined diameter the further lever is biassed toward itsengagement position in which the first arm engages the second outertoothing of the member and the sensor lever is allowed to move to renderthe vehicle-sensitive and belt-sensitive locking systems operable.
 2. Asafety belt reeling device according to claim 1, wherein said first armof said further lever has a first and a second end, said first endprovided with an engaging tip and said second end opposite said engagingtip extending past a pivoting axis of said further lever and providedwith a weight that biasses said further lever into said engagementposition.